1. Field of the Invention
The present invention illustrates a power system, and more particularly, a power system for inputting multi-voltage levels and/or outputting multi-voltage levels.
2. Description of the Prior Art
With the advancement of techniques, several portable electronic devices are widely adopted to our daily life, such as smart phone, personal digital assistant, tablet, micro-digital camera, and notebook. These portable electronic devices take advantage in high flexibility and high convenience. Specifically, in order to achieve high operation performance, enhancing a processing speed (i.e., floating processing speed) in conjunction with multi-functional processing core becomes a major trend of circuit design. However, with the improvement of processing speed, power consumption of the portable electronic device must be increased accordingly. Thus, when a capacity of a battery (or say, cell packs) is constrained to satisfy a microminiaturization volume, a working time (life span) of the portable electronic device may be reduced.
To extend the working time (life span) of the portable electronic device, a method is to use a power bank. Particularly, the power bank can be regarded as a portable battery with high capacity. By using the power bank to charge the portable electronic device, the working time (life span) of the portable electronic device can be extended. According to a standard of the power bank, an output voltage is fixed to 5V. An output current is fixed to 1 A or 2 A. Thus, the portable electronic device can be charged by using the standard power bank. However, the conventional power bank may not be able to charge another portable electronic device (i.e., smart phone or notebook) designed by a different standard because it may require a different charging voltage. In other words, the conventional power bank may not be compatible to the portable electronic device designed by a different standard. Further, a cell array of the conventional power bank is generally connected in series. Thus, when a cell (or some cells) of the cell array is abnormal, the output voltage becomes unstable, making the power bank unsafe.
Thus, it is important to develop a safe power system capable of inputting and/or outputting voltages with multi-voltage levels.